The role of human-induced climate change in heavy rainfall events such as the one associated with Typhoon Hagibis

Study key findings & significance

• More than 240 mm of rain fell in the Tokyo region on 12 October 2019, associated with tropical cyclone Hagibis. Human emissions of greenhouse gases made the extreme rainfall as the storm made landfall 67% more likely.
• Roughly $4 billion of the $10 billion damage in insured losses caused by the rainfall can be attributed to climate change.

Author quotes

“The negative consequences of the continued burning of fossil fuels are now evident and can be felt also in wealthy countries like Japan."

Friederike Otto, co-author and scientist who leads the World Weather Attribution effort

Abstract

Around October 12, 2019, torrential rainfall from Typhoon Hagibis caused large-scale flooding in a large area around the metropole region of Tokyo leading to large-scale destruction including losses of lives, livelihoods, and economic losses of well over $10 bn US dollars. In this paper we use a multi-method probabilistic event attribution framework to assess the role of human-induced climate change in the heavy rainfall event responsible for a large proportion of the damages. Combining different observational datasets and various climate model simulations, we find an increase in the likelihood of such an event to occur of 15–150%. We use this assessment and the calculated fraction of attributable risk (FAR) to further estimate the economic costs attributable to anthropogenic climate change based on the insured economic losses. Our conservative estimate is that ~$4bn of the damages due to the extreme heavy rainfall associated with Typhoon Hagibis are due to human-induced climate change.